Reading the many posts here I can see how hard it is for Dublin visitors to pick an accommodation that is going to be perfect for their Dublin stay.
Not too far from the city centre and not too far from the airport or ferry port. Close to where it is lively but not kept awake all night by being in or near areas that are too lively (all night!)
Safe areas to walk through at any hour of the day or night.
When visitors see photos on the different websites - is that exactly what they are going to hope to see/get on arrival?
Remember with many accommodations you get what you pay for - you may get a wonderful deal but you may have to sleep on your luggage for fear of it going missing!
Important to reserve with someone that knows what you are reserving and can help you,like Gruene - Insel. At least if you have any problems they can help you.